drm/hisilicon/kirin: Use the correct HiSilicon copyright

s/Hisilicon/HiSilicon/.
It should use capital S, according to
https://www.hisilicon.com/en.

Signed-off-by: Hao Fang <fanghao11@huawei.com>
Acked-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1621678529-14389-1-git-send-email-fanghao11@huawei.com